The present invention relates to a storage device and a computer system, and more particularly to a storage device for transferring stream data stored in a plurality of computers, storage devices or computer systems (hereafter referred to as “nodes”).
Consider a system in which a single computer for delivering data (hereafter referred to as “delivery server”) receives a data-delivery request from a client and this delivery server delivers data, which is stored in plural nodes (the delivery server is connected to those nodes through a network), in response to the data-delivery request. As a storage device for realizing the above-mentioned system, a network attached storage (NAS) devices mounting an NFS server module is known (“Nikkei System Provider”, Nikkei Business Publications, Inc., Mar. 30, 2001 issue, pp. 72–77, and “Open Design, No. 3, Ethernet and TCP/IP”, CQ Publishing Co., Ltd., pp. 91–99). “Ethernet” is a trademark of Fuji-Xerox Co., Ltd.
FIG. 1 is a diagram showing an example of a software system for realizing the above-mentioned data delivery using the NAS device mounting the NFS server module. In this software system, a delivery server 101 receives a delivery request from a client 103. In response to this delivery request, the delivery server 101 delivers, to the client data, data which is stored in the NAS devices 102 connected to the delivery server 101 through a network.
When receiving the delivery request from the client 103, the delivery server 101 activates a delivery engine module 105. The delivery engine module 105 issues a file-read request to an NFS client module 107 in order to read data, which is specified by the client, from the NAS device 102.
Subsequently, the delivery engine module 105 receives data from the NFS client module 107, and delivers the data to the client which issues the delivery request. A data registration module 106 issues a file-write request to the NFS client module 107 to store the data in the NAS device 102.
The NFS client module 107 receives the file-read request from the delivery engine module 105 or the file-write request from the data registration module 106. In response to the received request, the NFS client module 107 issues an NFS-read request or an NFS-write request to the NAS device 102.
The NAS device 102 receiving the NFS-write request or the NFS-read request from the delivery server 101 activates a file system module 109 and a disk driver module 110. The NAS device 102 executes a disk-write operation or a disk-read operation to a storage device 111 in response to the requests in the order of their arrival.